DE 199 44 620, which was published subsequently, discloses an aircraft passenger seat having individual seat components, including a leg rest and a backrest. These seat components can be moved by actuating means in the form of servo-drives or actuators which can be triggered by a hand-operated actuating means for adjusting the seat to the requirements of the respective seat occupant. For the seat parts, hand levers are modeled to the contours of these seat parts as part of the actuating means, are combined into a control for adjusting the aircraft passenger seat, and yield meaningful adjustment for the respective seat component. To prevent the seat occupant from striking fixed barriers when adjusting the seat components to his requirements, for example against the rear area of the backrest of a seat located forwardly in the lengthwise direction of the seat, for the servo-drives there are stops against which the respective seat components run. The pertinent respective stop barrier cannot be passed even as the pertinent control button continues to be actuated. Another possibility is to turn off the drive by cam-operated limit switches. The pertinent limiting barriers are not always approached without jerking in the known seat designs. This jerking adversely affects sitting comfort. The respective seat component is also protected by way of stops in the maximum deflection positions such that obvious harmonic motion of all seat components, for example, to “convert” the passenger seat from an upright position into the continuous fully reclined position is not at all possible without obstruction.
To eliminate the above-described defect, EP-B-0774913 discloses a generic motor vehicle or aircraft passenger seat having an electric control which acts on the leg rest to monitor the position of the leg rest position so that collision of the footrest, as an integral component of the leg rest, on the floor is prevented. To accomplish pertinent collision protection, the electronic control, by corresponding sensors, monitors both the actual position of the footrest and the actual position of the leg rest. In doing so, a signal output to the control corresponds to the footrest position and the current leg rest position. Furthermore, the electronic control is used to ascertain whether the footrest for at least one movement of the leg rest out of the leg rest position and when the footrest moves out of the footrest position will collide with the floor and to move the footrest out of the current position into a fixed, secure position if there is the danger that the footrest will touch the floor.
In the pertinent configuration, only one seat component in the form of a leg rest is monitored accordingly and triggered to prevent collision with the floor area. Other seat components, such as the seat part and/or the backrest, are not included, so that relative to these seat components a collision with stationary or other three-dimensional barriers cannot be precluded. Even if the control and monitoring means for the leg rest were to be transferred to the seat part and/or the backrest, possible collisions would only be prevented for the respective seat component, but not for the seat as a whole, since the indicated monitoring systems do not interact with one another. Optionally therefore, in the known approach, before the leg rest strikes the aircraft deck, a possible collision is detected and the entire seat kinematics is stopped and “frozen” in this position. This operation makes unobstructed motion of the entire seat impossible, and accordingly, adversely affects the sitting comfort. Joint motion of all seat components in the known approach is only possible to the extent that by actuating a single actuating button (magic button), all seat components can be moved from the fully reclined position into the upright position and vice versa.
DE-C-195 22 897 discloses an adjustable seat, especially in a motor vehicle, with several adjustment means. Each adjustment means is used for seat adjustment overall or for adjustment of one of the seat components in the pertinent adjustment direction. The first adjustment direction can be actuated by hand or by a servo-drive. One or more other adjustment directions can be actuated by the respective servo-drives. A sensor detects the set positions of the first adjustment means. In a storage, for each of the other adjustments means a characteristic is stored which fixes its theoretical set position depending on the set position of the first adjustment means according to ergonomic aspects. To carry out a seat adjustment process, first the set position desired for the first adjustment means is adjusted and is recognized by the control device by the sensor. Then, the control device, on request by actuating an assigned presetting control element, retrieves from the memory the pertinent theoretical set position for each of the other adjustment means and controls each of the other adjustment means by the corresponding triggering of the servo-drives into their theoretical set positions. In the known approach, therefore, adjustment takes place in two steps (preadjustment and main adjustment). In the preadjustment of one seat component, for example, the seat part is preadjusted in its lengthwise setting. Proceeding from this preadjustment, the other seat components trail, as for example the backrest or headrest, in their adjustment such that for an average seat occupant automatically increased comfort positions are reached depending on the lengthwise adjustment of the seat part. Based on the division into preadjustment and main adjustment, there is no continuous adjustment of all seat components to one another in a common manner. Collision protection, for example relative to the legs of individuals sitting in the back in the vehicle, is not attained.